ALONG SHORE 



135 



battering power of water is enormous, and it 

 always works more destruction on a shallow 

 coast than on a deep one. A cliff, for instance, 

 that has a shelving bottom leading up to it has 

 much more fury directed against it than one 

 with a base seated in deep water. The waves 

 will not rush forward and dash into spray 

 against the latter. On the contrary, they flood 

 up heavily and slowly, and seem to stop with- 

 out striking a blow, the crests dancing up 

 against each other rather than against the 

 rocks. The reasons for this will be apparent 

 if we consider for a moment the conditions 

 that make possible the " breaker " and the 

 " beach-comber." 



The surf breaks most violently over shoals or 

 along a shelving beach where the bottom of the 

 ocean bevels upward toward the shore. A 

 wave from the sea is pushed up this incline 

 with a swiftness proportionate to the propel- 

 ling force behind it. The friction or drag 

 upon the wave comes from the shelving bot- 

 tom ; and as the shore is neared this friction is 

 not only intensified by the increased abruptness 

 of the incline, but also by the flow outward of 

 those returning waters from the beach which 

 we call the "undertow." The result is, the 



